| 摘要 |
1,224,562. Etching. TEXAS INSTRUMENTS Inc. 24 April, 1968 [16 May, 1967 (2)], No. 19374/68. Heading B6J. [Also in Division H1] A cavity with a high depth to width ratio is etched in the surface of a body 10, Fig. 9, by directing an etchant fluid through an aperture 30 in a malleable mask 24a, and periodically bending the edges of the mask that extend over the cavity down into the cavity to protect the wells thereof, Fig. 14. The edges may be bent by brushing. The body 10 may comprise germanium semi-conductor material which is bonded to a degenerate semi-conductor substrate 12. The body 10 may be covered with a first chromium layer 22, a gold layer 24 and a second chromium layer 26. The layer 26 is etched through a photomask with hydrochloric acid and methyl alcohol in the presence of zinc dust to leave strips 26a, Fig. 7. The layer 24 is etched through a further photomask using potassium iodide and the layer 22 is then etched with a similar etchant to that used for layer 26. The apertures in layers 24 and 22 define aperture 30. After etching body 10 in a stream of hydrofluoric acid etching liquid, portions 24a of the gold layer are removed with potassium iodide and chromium strips 26a and the portions of the chromium layer 22a are removed with hydrochloric acid and methanol. |
